docs: add new header features

docs/docs.typ

@@ -198,7 +198,8 @@ Showing a number. #positional
 - Just add an `int` value with the number you would like to show. 
 
 Showing a text label for a number #positional
-- Add a content field after the int value which the label belongs to.
+- Add a content field after the int value which the label belongs to. 
+- To show a label without the number use the negativ number. _Example: (-5) instead of (5)_
 
 #info[
 Set the order of the bits with the `msb` argument directly on the `bytefield`.
@@ -221,6 +222,12 @@ You can use #named arguments to adjust the header styling.
 - `fill` argument adds an background color to the header.
 - `text-size` sets the size of the text.
 - `stroke` defines the border style.
+- `marker` [bool] defines if there is a marker line shown below the label. 
+	- `marker: true`: shows a marker on each label.
+	- `marker: false`: no marker is shown at all.
+	- `marker: (true,false)`: shows markers only on labels with numbers.
+	- `marker: (false, true)`: shows markers only on labels without numbers.
+
 
 === Numbers and Labels example
 You can also show labels and indexes by specifying a `content` after an `number` (`int`).

lib/api.typ

@@ -184,14 +184,24 @@
 ///   - `"bounds"` shows a number for every start and end bit of a field.
 ///   - `"offsets"` shows a number for every start bit of a field. 
 /// - numbers (auto, none): if none is specified no numbers will be shown on the header. This is useful to show only labels.
+/// - marker (bool, array): defines if marker lines are shown under a label.
+/// - angle (angle): The rotation angle of the label.
+/// - fill (color): The background of the header.
+/// - stroke (color): The border stroke of the header.
+/// - text-size(length): The text-size for the header labels and numbers.
 /// - ..args (int, content): The numbers and labels which should be shown on the header. 
 ///   The number will only be shown if it is inside the range.
 ///   If a `content` value follows a `int` value it will be interpreted as label for this number.
 ///   For more information see the _manual_.
 #let bitheader(
   range: (auto,auto),  
   autofill: auto,
-  numbers: auto,  
+  numbers: auto,
+  marker: true,
+  fill: auto,
+  stroke: auto,
+  text-size: auto,  
+  angle: -60deg,
   ..args
 ) = {
   // assertions